Conventionally, for example, as a fluid machine incorporated into a Rankine cycle device that recovers and reuses waste heat of a vehicle engine, a pump integrated expander, in which a pump that circulates working fluid such as refrigerant is integrally connected with a scroll type expander that expands heated and evaporated fluid, is known (see, for example, the Patent Document 1).
Furthermore, there is known a fluid machine integrally equipped with a plurality of rotating units as the pump integrated expander, in which machine an Oldham coupling is disposed between the plurality of rotating units, to separate each rotating unit at the Oldham coupling, so that an operation evaluation of each rotating unit can be performed individually (see, for example, the Patent Document 2).